HHS developing AI tool to analyze vaccine injury claims
The HHS is developing a generative AI tool to find patterns in unverified vaccine injury reports from the VAERS database and generate hypotheses about negative vaccine effects. Experts warn the tool could produce false alerts and be misused to support anti-vaccine claims, since VAERS data alone cannot establish vaccine causation.
What happened
The US Department of Health and Human Services is developing a generative artificial intelligence tool to find patterns across data reported to the Vaccine Adverse Event Reporting System (VAERS) and to generate hypotheses on negative effects of vaccines, according to an HHS AI inventory released in 2025.
The tool has not yet been deployed, according to the HHS document, and an AI inventory report from the previous year shows that it has been in development since late 2023.
Reported impact
Experts worry that the predictions generated by the tool could be misused. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia, stated: "I would expect, depending on the approaches used, a lot of false alerts and a need for a lot of skilled human follow-through."
VAERS data alone cannot be used to determine if a vaccine caused an adverse event, as the claims are unverified. Anti-vaccine activists have historically misused VAERS data to argue that vaccines are unsafe, despite CDC guidance that a VAERS report does not mean a vaccine caused an adverse event.
Index analysis
VAERS was established in 1990 as a hypothesis-generating mechanism to detect potential safety issues with vaccines after approval. Anyone, including members of the public, can submit an adverse reaction report to the database without verification.
Offit noted that VAERS is "a noisy system" with "no control group" that only shows adverse events occurring at some point following immunization, but does not prove causation.
Governance controls
VAERS is jointly managed by the Centers for Disease Control and Prevention and the Food and Drug Administration.
Classification
Sources and evidence
This record was researched and written by the Index, based on the following original reporting.